Thicker Than Water
by Dokuhan
Summary: Stiles appears one night. Stiles isn't happy. Derek is confused. (Minor not-really-crossover with the 80's movie)


A collaboration with nikki_kun05!

This is the slightest, loosest crossover with the 80's movie ever - it probably shouldn't even be considered a crossover really because like damn yo, can it really be like the 80's movie if it's not taking place in the 80's? Even though Rupert is pretty much the Stiles from that version? Who knows.

Beware, there's a bit of Sterek ahead.

* * *

Stiles sighed in relief as he closed the door, slightly ashamed of himself for practically pushing his dad out so he could make it to the station for his night shift an hour earlier than he really needed to. He grinned before bounding his way up the stairs, down the hallway, and into his room - wasting no time before opening up his window and yelling down, "He's gone! Get your furry butt up here now!"

He grabbed Derek before he had a chance to really make his way through the window, dragging him into a kiss. The older man responded enthusiastically as he finally climbed over the windowsill, putting both of his hands on Stiles' cheeks. "You're in a good mood..." he mumbled against his mouth.

"Three fucking weeks, Derek. It's been three fucking weeks since we last had sex." Stiles pulled Derek into another kiss, walking backwards towards his bed. "Three goddamn weeks of witches, a wandering unicorn, and my dad taking only morning shifts." The back of his knees hit the edge of his bed and he fisted Derek's shirt. "I want sex. Now."

Derek laughed, he actually laughed, because he was a smug as bastard and all Stiles wanted to do was punch him in the face. But then that would get in the way of their much needed sexy time. Plus it would hurt him more than it would hurt Derek. Maybe he would wait until after, when they were stuck together for the next half-hour or more, make a lot of noise so he couldn't fall asleep after. Yeah, that would show him.

Of course, all thoughts of revenge left Stiles' head as Derek pushed them both onto the bed with a little growl and of course Derek knew that was his weakness, since it made his knees weak enough to leave him splayed out.

Fine, if he was going to play dirty Stiles could do that too.

He slid his hands up Derek's henley, running his thumbs over his hipbones. Derek moaned and gave Stiles this look, like he was caught between rolling over like a puppy and strangling him. Instead he wound up attacking Stiles' neck, slightly elongated teeth scraping against the skin.

"You're right..." Derek mumbled, his hands reaching down to the hem of Stiles' t-shirt, "it's been too long." He pressed his lips against Stiles' again, his tongue moving just the right way as he slid Stiles' shirt up. He only pulled away to lift it over his head, and to help out when the t-shirt and the flannel he had been wearing got tangled up in each other.

Stiles threw the shirts to the floor before pointing at Derek's leather jacket, licking his lips. "Take this off." He started pushing it off the man's shoulders. "Take it off right now."

Derek pulled away just enough, his legs still straddling Stiles' hips, to pull the jacket off. He pulled his own shirt off without being asked, never really breaking eye contact with Stiles.

"Jesus Christ..." Stiles mumbled, sitting up as much as he could. He ran his hands over Derek's chest, sliding up to his neck. "You're hot."

Derek rolled his eyes, but kissed Stiles again. He started lowering Stiles back down, but then suddenly stopped, looking towards the door. "Someone just came in your front door."

Stiles frowned and tried to pull Derek back into what they were doing, "It's probably just Dad, he probably forgot something." He ran his fingers through the hair on the back of Derek's head. "Come on."

"He sounds like he's coming up the stairs." He started to get up like he was going to leave, and hell fucking no.

Stiles dragged Derek back down, pulling him into the sloppiest kiss he could muster. "Ignore him, come on, sourwolf." He canted his hips up, making sure his crotch met Derek's at just the right angle. He stifled Derek's moan with another kiss.

The kiss was short lived as the door suddenly slammed open and in crashed someone who was definitely not his dad.

"Guess who came to visit, baby cousin!"

"Ohmygod!"

"What the hell is going on?!"

Derek didn't even react as he was pushed off the bed and fell to the floor on his ass. Resisting the urge to growl Derek fixed his gaze to the stranger in the doorway. He looked fit and average sized, dressed in a simple black t-shirt tucked into tight blue jeans with sunglasses sitting on top of his head. His hair was a light brown and kind of flopped over his forehead, making the bit of a wave it had more prominent. He began to slowly make his way inside the room, obviously displeased.

He stopped to glare at Derek before turning to Stiles, "who the hell is this?"

"It's none of your business!" Stiles ran a frustrated hand through his hair. "Rupert, what are you even doing here anyway?"

"I'm family! I came to check in on you and Uncle Johnny only to find you in the arms of Captain Homo here!" He pointed to Derek as if to emphasize the point. "I ask again, what the hell is going on?"

Stiles pursed his lips as he thought of what to say. "You just called my boyfriend Captain Homo."

"Boyfriend? Coz are you really that desperate to get laid cuz you shouldn't have to be," he crossed his arms. "Stilinski men are irresistible to the ladies you're just going about it the wrong way."

Derek cleared his throat and both Stilinskis looked at him.

"Your services are no longer needed, Captain Homo," he pointed to the door. "Exit's that way."

"Ohmygod! Do you even listen to yourself? Derek stay where you are, he's the one who's leaving."

Rupert scoffed, looking incredulous, "I come here all the way from LA and this is how you treat me, Zbigniew?"

"Zpee-neef?" Derek arched an eyebrow, completely butchering Stiles' real name.

"It's Stiles! STILES."

"I go by Stiles and you're Zbigniew. We've been over this how many times? I know you admire me, but that doesn't mean you can steal my nickname."

"Ohmygod, shut up!"

Derek cleared his throat, making the both of them turn towards him. "As much as I'd love to hear you two argue the rest of the day, maybe someone could explain what's going on?"

Rupert rolled his eyes as he reached for the pile of clothes on the floor, grabbing them then throwing them, aiming at Derek's head. "You, Captain Homo, are going to get dressed and then you're going to take your faggoty ass out of my cousin's house. And we better not see you ever again or I'll kick your ass, capiche?"

His boyfriend gave Rupert an exasperated look as he reached into the pile, pulling out a t-shirt with a skull on it, "First off all, half of these are Stiles', second, I don't take orders from people who come barging in like they own the place." He dropped the clothes on to the bed, crossing his arms over his chest. "Stiles?"

Stiles glared at Rupert, "This asshole is my cousin, Rupert Stilinski. The same Rupert that should be in LA and probably in his psychology class at school right now."

Rupert scoffed. "I was Stiles before he was born so you will not be addressing me as Rupert, especially not you Faggot-face. And besides I decided to take a vacation and chose to spend it seeing my favorite uncle and cousin. How can you call me an asshole, coz? Where's the love?"

"It's the middle of the fucking semester!"

"So?"

"Do Aunt Sandra and Uncle Alex even know you're here?!"

"What they don't know won't hurt them."

"Stiles, do you want me to get rid of him?"

Rupert arched a brow, in his attempt to protect his cousin's virtue he had failed to notice Derek's kind of awesome physique. Derek was about as tall as Stiles, who had a couple of inches over his cousin, and had a lot more muscle was no doubt in Rupert's mind that Derek could easily get rid of him. But with what he lacked in muscle, he made up for in brains. "Fine. Get rid of me. Guess I'll just have to go to the station and ask good ol' Uncle Johnny if I can stay..." he gave Stiles this look that automatically spelled trouble, "I just hope I don't let your little gay rendezvou slip while I'm there."

Stiles let his jaw drop while Derek shot him a worried look. That bastard, he wouldn't. "Don't you dare."

"Then direct me to my quarters, Zbigniew." Rupert gave Derek a pointed look, "And I expect Captain Homo to be making his way out of here while we're gone."

Rupert turned on his heel and walked out the door, leaving Stiles steaming. Derek just scowled and handed him his shirts, mumbling something about low blows. There was no way he could have been as pissed off as Stiles was in that moment. He was going to get his revenge, and it was going to be sweet.

Since Stiles loves his dad very much he called him to tell him about their unexpected houseguest.

"Rupert's here."

He didn't even have to see his dad to know he had that look on his face. The look that said "you gotta be kidding me", the look Stiles was way too used to getting. "Your aunt and uncle didn't say anything about coming to visit any time soon..." he started tentatively.

"They're not here. Just Rupert."

He sensed that his dad was probably pinching the bridge of his nose now. "I swear...that kid."

"He didn't even ring the bell, he just barged right in. Now he won't leave, should I call Aunt Sandra?"

"No, no I'll handle it. Just tell him not to get too comfortable."

"Can do, Dad." He knew there wasn't much of a point in trying, though, since Rupert would just ignore him and do whatever he felt like because he was "the older and wiser one" and kind of an ass.

His dad sighed on the other end. "Anyway, thanks kid. I'll see you later, alright?"

"Yeah...see you for dinner." He frowned a bit as he hung up the phone, wondering what to do about his cousin.

"So what'd Uncle Johnny have to say?" Rupert asked as he rooted around the fridge before grabbing a jar of pickles. He tried opening the jar, twisting the cap as forcefully as he could. He stopped and looked at Stiles. "A little help here?"

Stiles rolled his eyes. "Put it under the faucet or something."

His cousin shrugged but put the jar under water and after another attempt the jar opened with ease. "Well whattya know," he grinned as he nodded to Stiles before taking a bite of pickle. "Thanks coz."

Stiles just looked unimpressed. "How long are you planning on hanging around here?"

"I haven't really decided yet, y'know?" he took another bite before hopping up onto the counter, "I was thinking about traveling across the country, maybe head for Vegas or New York or something, but I figured - why not visit family before I start my bodacious journey?"

"Did you really just use the word 'bodacious' in a sentence? What are you, from 1985?"

His cousin just ignored him. "You should whip up some flour or something I bet if I deep fry these they'd taste out of this world."

Stiles rolled his eyes, "Dad said not to get too comfortable, Rupert. You're not staying."

Rupert just looked unconcerned. "Maybe I should make dinner for us."

"He's probably calling Aunt Sandra right now..."

"Hmm...maybe I'll make some mac n cheese." He set the jar of pickles down before getting off the counter. "You guys do have mac n cheese, right?"

"I'm surprised she hasn't already shown up to drag your ass back down to LA."

Rupert strode over to the cabinets and looked in them until he found two boxes of Kraft macaroni and cheese.

"And you're not even listening, of course. Why would I expect any different." Stiles sat down at the kitchen table, putting his head in his hands. He knew there wouldn't be a point in trying.

"I'm listening," Rupert began as he got things out to make dinner. "Doesn't mean I have to stop what I'm doing just because you open your mouth."

Stiles just narrowed his eyes as his cousin prepared the food. He still wanted to tear the other man apart limb from limb for infringing on his and Derek's personal time, not to mention trying to use what he walked in on to his advantage and using his birth name. No one called him Zbigniew. Ever. Only his grandmother was allowed to do that.

Rupert continued to make dinner, mouth still running even though Stiles wasn't participating in any conversation. Unless grunting at random things counted as conversation. Blah blah blah his friend Scott (ridiculous coincidence, right?) blah blah blah parties blah chicks blah righteousness...oh god why was his cousin stuck in the 80's? Next he would be talking about "surfing" on top of cars and how he managed to trick the liquor store owner into selling him a keg. Stiles couldn't help but wonder how he could be related to someone like Rupert.

"And dinner is cooked!"

Stiles almost jumped at the harsh sound of the lid clanging against the metal of the pot.

"Jesus..."

His cousin just looked pleased with himself as if following the instructions on the back of boxes of kraft macaroni was a difficult task.

"So what happened to the lovely Lydia?" Rupert prompted as he took a seat at the kitchen table with Stiles. "I thought you had a plan, Coz."'

A long time ago, he actually looked up to his cousin. He would tell him about everything going on in his life and Rupert for the most part wasn't a dick about it. He'd hear him out about how he wanted to be good enough to play high school lacrosse ("basketball is better, coz") or whatever stupid thing him and Scott were up to ("Seriously, how the hell do we both have friends named Scott? Let's just call your Scott 'Inhaler-boy', ok? I don't want to be confused"), and even his plans to woo Lydia. Rupert laughed and teased at first before smiling and telling him, "just give her a reason to look your way, coz."

But that was a long time ago and he was past his old feelings for Lydia. They were friends now, and nothing more - and he was perfectly happy with that, he had someone else to fill that roll.

"Plans change," he managed to say before getting up.

Rupert quirked a brow.

"Hope this stuff is good." Stiles looked over the food. It smelled good, sure, but he'd been deceived by nice smelling things before.

"Oh, it is." Rupert puffed up his chest in pride.

"Yeah, we'll see," Stiles muttered as his eyes found the clock.

He wished time would go by faster, because when you thought about it too long, a half and hour felt like a century. As soon as his dad came home the quicker they could send his cousin his way home, and Stiles couldn't help but feel a little mean thinking that.


End file.
